The present invention relates to an improved polyarylene sulfide resin composition and a process for producing the same. More particularly, the present invention is concerned with a polyarylene sulfide resin composition having excellent impact resistance and heat resistance, comprising a resin component composed of a polyarylene sulfide resin and a polyester resin and, blended and melt-kneaded therewith, a specified epoxy-containing compound and, if necessary, a radical initiator, and a process for producing the same.
In recent years, a thermoplastic resin having high heat resistance, high chemical resistance and, further, flame retardancy has been required as the material of construction for electrical and electronic equipment, automobiles and chemical equipment.
A polyarylene sulfide resin represented by polyphenylene sulfide is one of the resins capable of meeting the above-described requirement and has been in increased demand also by virtue of having excellent properties relative to the cost of the resin. Polyphenylene sulfide resin, however, has a severe drawback in that it is inferior in toughness and more fragile than engineering plastics such as polyacetal, nylon, polycarbonate and polybutylene terephthalate.
The incorporation of a fibrous reinforcement, such as a glass fiber or a carbon fiber, or other filler is known as a means for solving the above-mentioned problem. The addition of a fibrous reinforcement contributes to a remarkable improvement in the performance, such as strength, rigidity, toughness and heat resistance of the resin. Even when the above-described reinforcement is incorporated, however, the toughness of polyphenylene sulfide is inferior to that of other engineering plastics, which often limits the use of polyphenylene sulfide in many applications despite the excellent chemical resistance, heat resistance and flame retardancy of the resin.
On the other hand, polymer blending of the polyarylene resin with a flexible polymer is a promising method for improving the impact resistance. This method, however, has drawbacks such as the surface of the molded article being liable to peel away as there exists only a few flexible polymers which have excellent heat and chemical resistances. Moreover, the flexible polymers have poor compatibility with polyarylene sulfide resin. Accordingly this blending method cannot provide a polyarylene sulfide resin composition having improved mechanical and physical properties, such as toughness and impact resistance, without detriment to the features inherent in the polyarylene sulfide resin.
The present inventors have made intensive studies on a polyarylene sulfide resin composition having high toughness and impact resistance and a process for producing the same and, as a result, have found that the addition of a silane compound having an alkoxysilane group to a resin component comprising a polyarylene sulfide resin and a polyester resin contributes to an improvement in the impact resistance, and have filed a patent application concerning this finding as Japanese Patent Application No. 197003/1990. According to the above-described composition and process for producing the same, although good toughness and impact resistance can be obtained, there is a tendency that the melt viscosity becomes so high as to inhibit the production of a thin-walled molded article by injection molding or the like. The solution to this problem has been desired in the art.